So far, when a hard coating is to be formed on the surface of a formed body such as injection-formed body, means is usually employed in which a formed body obtained in advance is coated by dipping with a coating solution for forming hard coating followed by curing to form the hard coating. This means is free of problem if the formed body is of a flat shape such as a sheet. If the formed body has a solid shape including dents and protuberances on the surfaces thereof, however, the coating solution cannot be uniformly applied or the liquid cannot be cut well from the formed body arousing such a problem that the thickness of the coated solution becomes uneven giving rise to the formation of striped patterns.
To avoid the above problem, in recent years, there has been employed means (also called insert forming or in-mold forming) according to which a transparent thermoplastic resin sheet forming a hard coating on the surface thereof is used as a substrate for forming, the substrate for forming is placed in a forming metal mold such as for injection forming, the substrate is shaped in a predetermined shape while being heated and, thereafter, a predetermined resin is injected into the metal mold and is cured (patent documents 1 to 3).